Now i get the very same hangs (hang while detecting the VIA USB1.1 controllers)
independently from the irq usage pattern, it seems, on a totally different box --
a i440ZX-based pIII machine with an old BIOS (pre-99).
I run both with acpi turned off (default parameters; the kernel turns it off
automagically due to the anciency of the BIOS) and with acpi=force; the resulting
variation is zero.
(Well, i`ve actually reported this problem somewhere back in the 2.5.5x times...)
I`m going to test it with 2.6.1 soon.
regards, Samium Gromoff